Disclosed herein are inventions relating to high temperature-resistant thermoplastic polymers of norbornene dicarboximides and to methods of making and using such polymers. More particular aspects include inventions relating to polymers of N-phenyl norbornene dicarboximide.
High temperature resistance, e.g. as measured by heat distortion temperature and glass transition temperature (T.sub.g), is provided in several existing polymer systems, e.g. the polyether imides and the polyamide-imides. In addition to high strength and high modulus, a desirable characteristic of such polymer systems includes processability like more conventional lower temperature thermoplastic polymers.
McKeon et al. in U.S. Pat. No. 3,330,815 disclose the vinyl-type addition polymerization of a variety of norbornene derivatives, including carboximides, to provide polymers free of unsaturation in the chain. Such polymerization is carried out with noble metal catalyst, i.e. palladium compounds.
Reding et al. in U.S. Pat. No. 3,494,897 disclose the vinyl-type addition polymerization including copolymerization with alkenes, of a variety of norbornene derivatives to provide polymers of saturated chains. Such polymerization of copolymers of norbornene derivatives including dicarboximides (see for instance Examples 24 and 25) is carried out in the presence of a free-radical catalyst, e.g. a peroxide.
See also French Brevet d'invention No. 1,594,934 which discloses polymerization of norbornene dicarboximides with noble metal catalyst, e.g. ruthenium compounds. Analyses reported by Michelotti et al. in Journal of Polymer Science 3 (1965) pp 895-905 suggest that ruthenium catalysts may effect polymerization to some extent through a bicyclic double bond without ring opening (see Michelotti et al. at p. 902).
Such noble-metal-catalyzed imide polymers as reported in Brevet No. 1,594,934 have somewhat low glass transition temperatures (Tg). See, for instance, Example 2 which reports the preparation of a polymer of N-methyl norbornene dicarboximide having a Tg of 185.degree. C. See also Example 14 which reports the preparation of a polymer of N-phenyl norbornene dicarboximide having a Tg of 162.degree. C. In this regard see the Comparative Example, herein, which indicates that the substantially no polymerization results from the experimental procedure reported in Brevet No. 1,594,934, that the recovered material is substantially monomer, and that the reported Tg corresponds to a melting point.
Kurosawa et al., in U.S. Pat. No. 3,959,234 disclose the ring-opening polymerization of norbornene dicarboximides with a catalyst system comprising organic aluminum compounds and tungsten and/or molybdenum compounds. However, multiple polymerization mechanisms may have been involved perhaps due to contaminated catalyst since the tungsten-catalyzed polymers of the working examples are reported as having Tg's similar to the noble metal-catalyzed polymers reported in Brevet No. 1,594,934. In this regard in the U.S. Patent poly (N-methyl norbornene dicarboximide) is reported to have a Tg of 189.degree. C.; in the Brevet a Tg of 185.degree. C. is reported. Similarly, in the U.S. Patent poly (N-phenyl norbornene dicarboximide) is reported to have a Tg of 166.degree. C.; in the Brevet the Tg is 162.degree. C.
Other attempts at the metathesis ringopening polymerization of norbornene dicarboximides have met with apparently limited success. For instance, see Matsumoto et al. at ACS Symposium Series 59 (1977), page 303, who report poor polymer yield (i.e. about 8 percent) in attempts to polymerize monomers of norbornene dicarboximide and N-propyl norbornene dicarboximide. The preparation of monomers by Matsumoto et al. suggests that endo stereoisomers of the dicarboximides were used. Related work by Matsumoto is found in U.S. Pat. No. 4,039,491, e.g. in Example 20, where low molecular weight polymers of N-propyl norbornene dicarboximide were apparently obtained especially since polymerization was carried out in the presence of 1-hexene, a molecular weight limiting material.